Fahlstedt, M; Halldin, P; Kleiven, S
The protective effect of a helmet in three bicycle accidents--A finite element study Journal Article
In: Accident Analysis & Prevention, vol. 91, pp. 135–143, 2016.
Abstract | BibTeX | Tags: *Accidents, *Bicycling/in [Injuries], *Brain Concussion/pc [Prevention & Control], *Head Protective Devices, *Skull Fractures/pc [Prevention & Control], Computer simulation, Craniocerebral Trauma/pc [Prevention & Control], finite element analysis, Humans, Traffic
@article{Fahlstedt2016,
title = {The protective effect of a helmet in three bicycle accidents--A finite element study},
author = {Fahlstedt, M and Halldin, P and Kleiven, S},
year = {2016},
date = {2016-01-01},
journal = {Accident Analysis \& Prevention},
volume = {91},
pages = {135--143},
abstract = {There is some controversy regarding the effectiveness of helmets in preventing head injuries among cyclists. Epidemiological, experimental and computer simulation studies have suggested that helmets do indeed have a protective effect, whereas other studies based on epidemiological data have argued that there is no evidence that the helmet protects the brain. The objective of this study was to evaluate the protective effect of a helmet in single bicycle accident reconstructions using detailed finite element simulations. Strain in the brain tissue, which is associated with brain injuries, was reduced by up to 43% for the accident cases studied when a helmet was included. This resulted in a reduction of the risk of concussion of up to 54%. The stress to the skull bone went from fracture level of 80 MPa down to 13-16 MPa when a helmet was included and the skull fracture risk was reduced by up to 98% based on linear acceleration. Even with a 10% increased riding velocity for the helmeted impacts, to take into account possible increased risk taking, the risk of concussion was still reduced by up to 46% when compared with the unhelmeted impacts with original velocity. The results of this study show that the brain injury risk and risk of skull fracture could have been reduced in these three cases if a helmet had been worn.Copyright © 2016 Elsevier Ltd. All rights reserved.},
keywords = {*Accidents, *Bicycling/in [Injuries], *Brain Concussion/pc [Prevention \& Control], *Head Protective Devices, *Skull Fractures/pc [Prevention \& Control], Computer simulation, Craniocerebral Trauma/pc [Prevention \& Control], finite element analysis, Humans, Traffic},
pubstate = {published},
tppubtype = {article}
}
Johnson, K L; Chowdhury, S; Lawrimore, W B; Mao, Y; Mehmani, A; Prabhu, R; Rush, G A; Horstemeyer, M F
Constrained topological optimization of a football helmet facemask based on brain response Journal Article
In: Materials and Design, vol. 111, pp. 108–118, 2016.
Abstract | Links | BibTeX | Tags: Accident prevention, ALGORITHMS, brain, Concussion, Constrained optimization, Design, Design optimization, finite element analysis, Finite element method, football helmet, Fuel additives, Genetic algorithms, Multiobjective optimization, Optimization, Safety devices, Shear strain, Sports, Surrogate model, Surrogate modeling, Topology, Traumatic Brain Injuries, traumatic brain injury
@article{Johnson2016a,
title = {Constrained topological optimization of a football helmet facemask based on brain response},
author = {Johnson, K L and Chowdhury, S and Lawrimore, W B and Mao, Y and Mehmani, A and Prabhu, R and Rush, G A and Horstemeyer, M F},
doi = {10.1016/j.matdes.2016.08.064},
year = {2016},
date = {2016-01-01},
journal = {Materials and Design},
volume = {111},
pages = {108--118},
abstract = {Surrogate model-based multi-objective design optimization was performed to reduce concussion risk during frontal football helmet impacts. In particular, a topological decomposition of the football helmet facemask was performed to formulate the design problem, and brain injury metrics were exploited as objective functions. A validated finite element model of a helmeted human head was used to recreate facemask impacts. Due to the prohibitive computational expense of the full scale simulations, a surrogate modeling approach was employed. An optimal surrogate model selection framework, called Concurrent Surrogate Model Selection, or COSMOS, was utilized to identify the surrogate models best suited to approximate each objective function. The resulting surrogate models were implemented in the Non-dominated Sorting Genetic Algorithm II (NSGA-II) optimization algorithm. Constraints were implemented to control the solid material fraction in the facemask design space, and binary variables were used to control the placement of the facemask bars. The optimized facemask designs reduced the maximum tensile pressure in the brain by 7.5% and the maximum shear strain by a remarkable 39.5%. This research represents a first-of-its-kind approach to multi-objective design optimization on a football helmet, and demonstrates the possibilities that are achievable in improving human safety by using such a simulation-based design optimization. © 2016 Elsevier Ltd},
keywords = {Accident prevention, ALGORITHMS, brain, Concussion, Constrained optimization, Design, Design optimization, finite element analysis, Finite element method, football helmet, Fuel additives, Genetic algorithms, Multiobjective optimization, Optimization, Safety devices, Shear strain, Sports, Surrogate model, Surrogate modeling, Topology, Traumatic Brain Injuries, traumatic brain injury},
pubstate = {published},
tppubtype = {article}
}
Oeur, R A; Karton, C; Post, A; Rousseau, P; Hoshizaki, T B; Marshall, S; Brien, S E; Smith, A; Cusimano, M D; Gilchrist, M D
In: Journal of Neurosurgery, vol. 123, no. 2, pp. 415–422, 2015.
Abstract | Links | BibTeX | Tags: accident, Accident reconstruction, accidental injury, Accidents, Adolescent, adult, Article, Biomechanical Phenomena, Biomechanics, brain, brain concussion, brain stem, brain tissue, Cerebellum, clinical article, comparative study, Concussion, controlled study, Female, finite element analysis, Finite element modelling, gray matter, Hematoma, human, Humans, Hybrid iii headform, injury severity, laboratory test, Male, Mechanical, mechanical stress, middle aged, pathology, Pathophysiology, Persistent postconcussive symptoms, PHYSIOLOGY, Post Hoc Analysis, Post-Concussion Syndrome, postconcussion syndrome, priority journal, shear stress, simulation, SPORTS medicine, STATISTICAL significance, Stress, stress strain relationship, Subdural, subdural hematoma, traumatic brain injury, white matter, Young Adult
@article{Oeur2015,
title = {A comparison of head dynamic response and brain tissue stress and strain using accident reconstructions for concussion, concussion with persistent postconcussive symptoms, and subdural hematoma},
author = {Oeur, R A and Karton, C and Post, A and Rousseau, P and Hoshizaki, T B and Marshall, S and Brien, S E and Smith, A and Cusimano, M D and Gilchrist, M D},
doi = {10.3171/2014.10.JNS14440},
year = {2015},
date = {2015-01-01},
journal = {Journal of Neurosurgery},
volume = {123},
number = {2},
pages = {415--422},
abstract = {Object Concussions typically resolve within several days, but in a few cases the symptoms last for a month or longer and are termed persistent postconcussive symptoms (PPCS). These persisting symptoms may also be associated with more serious brain trauma similar to subdural hematoma (SDH). The objective of this study was to investigate the head dynamic and brain tissue responses of injury reconstructions resulting in concussion, PPCS, and SDH. Methods Reconstruction cases were obtained from sports medicine clinics and hospitals. All subjects received a direct blow to the head resulting in symptoms. Those symptoms that resolved in 9 days or fewer were defined as concussions (n = 3). Those with symptoms lasting longer than 18 months were defined as PPCS (n = 3), and 3 patients presented with SDHs (n = 3). A Hybrid III headform was used in reconstruction to obtain linear and rotational accelerations of the head. These dynamic response data were then input into the University College Dublin Brain Trauma Model to calculate maximum principal strain and von Mises stress. A Kruskal-Wallis test followed by Tukey post hoc tests were used to compare head dynamic and brain tissue responses between injury groups. Statistical significance was set at p \< 0.05. Results A significant difference was identified for peak resultant linear and rotational acceleration between injury groups. Post hoc analyses revealed the SDH group had higher linear and rotational acceleration responses (316 g and 23,181 rad/sec2, respectively) than the concussion group (149 g and 8111 rad/sec2, respectively; p \< 0.05). No significant differences were found between groups for either brain tissue measures of maximum principal strain or von Mises stress. Conclusions The reconstruction of accidents resulting in a concussion with transient symptoms (low severity) and SDHs revealed a positive relationship between an increase in head dynamic response and the risk for more serious brain injury. This type of relationship was not found for brain tissue stress and strain results derived by finite element analysis. Future research should be undertaken using a larger sample size to confirm these initial findings. Understanding the relationship between the head dynamic and brain tissue response and the nature of the injury provides important information for developing strategies for injury prevention. © AANS, 2015.},
keywords = {accident, Accident reconstruction, accidental injury, Accidents, Adolescent, adult, Article, Biomechanical Phenomena, Biomechanics, brain, brain concussion, brain stem, brain tissue, Cerebellum, clinical article, comparative study, Concussion, controlled study, Female, finite element analysis, Finite element modelling, gray matter, Hematoma, human, Humans, Hybrid iii headform, injury severity, laboratory test, Male, Mechanical, mechanical stress, middle aged, pathology, Pathophysiology, Persistent postconcussive symptoms, PHYSIOLOGY, Post Hoc Analysis, Post-Concussion Syndrome, postconcussion syndrome, priority journal, shear stress, simulation, SPORTS medicine, STATISTICAL significance, Stress, stress strain relationship, Subdural, subdural hematoma, traumatic brain injury, white matter, Young Adult},
pubstate = {published},
tppubtype = {article}
}
Patton, D A; McIntosh, A S; Kleiven, S
In: Journal of Applied Biomechanics, vol. 31, no. 4, pp. 264–268, 2015.
Abstract | Links | BibTeX | Tags: Article, Biomechanics, brain, Brain Injury, brain region, clinical article, Concussion, corpus callosum, Damage detection, evaluation study, finite element analysis, Finite element head models, Finite element method, Finite element simulations, football, gray matter, Head Injuries, head injury, human, Intra-cranial pressure, intracranial pressure, investigative procedures, Maximum principal strain, mesencephalon, Modeling, Models, Numerical reconstruction, Qualitative observations, Sport, sport injury, Sports, Strain and strain rates, Strain rate, Stress, thalamus, Tissue, tissue level
@article{Patton2015,
title = {The biomechanical determinants of concussion: Finite element simulations to investigate tissue-level predictors of injury during sporting impacts to the unprotected head},
author = {Patton, D A and McIntosh, A S and Kleiven, S},
doi = {10.1123/jab.2014-0223},
year = {2015},
date = {2015-01-01},
journal = {Journal of Applied Biomechanics},
volume = {31},
number = {4},
pages = {264--268},
abstract = {Biomechanical studies of concussions have progressed from qualitative observations of head impacts to physical and numerical reconstructions, direct impact measurements, and finite element analyses. Supplementary to a previous study, which investigated maximum principal strain, the current study used a detailed finite element head model to simulate unhelmeted concussion and no-injury head impacts and evaluate the effectiveness of various tissue-level brain injury predictors: strain rate, product of strain and strain rate, cumulative strain damage measure, von Mises stress, and intracranial pressure. Von Mises stress was found to be the most effective predictor of concussion. It was also found that the thalamus and corpus callosum were brain regions with strong associations with concussion. Tentative tolerance limits for tissue-level predictors were proposed in an attempt to broaden the understanding of unhelmeted concussions. For the thalamus, tolerance limits were proposed for a 50% likelihood of concussion: 2.24 kPa, 24.0 s-1, and 2.49 s-1 for von Mises stress, strain rate, and the product of strain and strain rate, respectively. For the corpus callosum, tolerance limits were proposed for a 50% likelihood of concussion: 3.51 kPa, 25.1 s-1, and 2.76 s-1 for von Mises stress, strain rate, and the product of strain and strain rate, respectively. © 2015 Human Kinetics, Inc.},
keywords = {Article, Biomechanics, brain, Brain Injury, brain region, clinical article, Concussion, corpus callosum, Damage detection, evaluation study, finite element analysis, Finite element head models, Finite element method, Finite element simulations, football, gray matter, Head Injuries, head injury, human, Intra-cranial pressure, intracranial pressure, investigative procedures, Maximum principal strain, mesencephalon, Modeling, Models, Numerical reconstruction, Qualitative observations, Sport, sport injury, Sports, Strain and strain rates, Strain rate, Stress, thalamus, Tissue, tissue level},
pubstate = {published},
tppubtype = {article}
}
Bartsch, A; Samorezov, S; Benzel, E; Miele, V; Brett, D
Validation of an "Intelligent Mouthguard" Single Event Head Impact Dosimeter Journal Article
In: Stapp Car Crash Journal, vol. 58, pp. 1–27, 2014.
Abstract | BibTeX | Tags: *Acceleration, *Boxing, *Brain Injuries, *Football, *Mouth Protectors, *Telemetry, ALGORITHMS, Biomechanical Phenomena/ph [Physiology], Boxing/in [Injuries], Boxing/ph [Physiology], Brain Injuries/di [Diagnosis], Brain Injuries/et [Etiology], Brain Injuries/pc [Prevention & Control], Brain Injuries/pp [Physiopathology], finite element analysis, Football/in [Injuries], Football/ph [Physiology], Head Protective Devices, Humans, Reproducibility of Results, Telemetry/is [Instrumentation], Telemetry/mt [Methods]
@article{Bartsch2014,
title = {Validation of an "Intelligent Mouthguard" Single Event Head Impact Dosimeter},
author = {Bartsch, A and Samorezov, S and Benzel, E and Miele, V and Brett, D},
year = {2014},
date = {2014-01-01},
journal = {Stapp Car Crash Journal},
volume = {58},
pages = {1--27},
abstract = {Dating to Colonel John Paul Stapp MD in 1975, scientists have desired to measure live human head impacts with accuracy and precision. But no instrument exists to accurately and precisely quantify single head impact events. Our goal is to develop a practical single event head impact dosimeter known as "Intelligent Mouthguard" and quantify its performance on the benchtop, in vitro and in vivo. In the Intelligent Mouthguard hardware, limited gyroscope bandwidth requires an algorithm-based correction as a function of impact duration. After we apply gyroscope correction algorithm, Intelligent Mouthguard results at time of CG linear acceleration peak correlate to the Reference Hybrid III within our tested range of pulse durations and impact acceleration profiles in American football and Boxing in vitro tests: American football},
keywords = {*Acceleration, *Boxing, *Brain Injuries, *Football, *Mouth Protectors, *Telemetry, ALGORITHMS, Biomechanical Phenomena/ph [Physiology], Boxing/in [Injuries], Boxing/ph [Physiology], Brain Injuries/di [Diagnosis], Brain Injuries/et [Etiology], Brain Injuries/pc [Prevention \& Control], Brain Injuries/pp [Physiopathology], finite element analysis, Football/in [Injuries], Football/ph [Physiology], Head Protective Devices, Humans, Reproducibility of Results, Telemetry/is [Instrumentation], Telemetry/mt [Methods]},
pubstate = {published},
tppubtype = {article}
}
Kettner, M; Ramsthaler, F; Potente, S; Bockenheimer, A; Schmidt, P H; Schrodt, M
Blunt force impact to the head using a teeball bat: systematic comparison of physical and finite element modeling Journal Article
In: Forensic Science, Medicine & Pathology, vol. 10, no. 4, pp. 513–517, 2014.
Abstract | BibTeX | Tags: *Computer Simulation, *Forensic Pathology/mt [Methods], *HEAD injuries, *Models, *Skull Fractures/pa [Pathology], *Skull/pa [Pathology], *Sports Equipment, *Weapons, Anatomic, Biological, Biomechanical Phenomena, Closed/pa [Pathology], Equipment Design, finite element analysis, Humans, Skull/in [Injuries], violence, Wood, Young Adult
@article{Kettner2014,
title = {Blunt force impact to the head using a teeball bat: systematic comparison of physical and finite element modeling},
author = {Kettner, M and Ramsthaler, F and Potente, S and Bockenheimer, A and Schmidt, P H and Schrodt, M},
year = {2014},
date = {2014-01-01},
journal = {Forensic Science, Medicine \& Pathology},
volume = {10},
number = {4},
pages = {513--517},
abstract = {Blunt head trauma secondary to violent actions with various weapons is frequently a cause of injury in forensic casework; differing striking tools have varying degrees of injury capacity. The systematic approach used to examine a 19-year-old student who was beaten with a wooden teeball bat will be described. The assailant stopped beating the student when the teeball bat broke into two pieces. The surviving victim sustained bruises and a forehead laceration. The State's Attorney assigned a forensic expert to examine whether the forces exerted on the victim's head (leading to the fracture of the bat) were potentially life threatening (e.g. causing cranial bone fractures). Physical modeling was conducted using a pigskin-covered polyethylene end cap cushioned by cellulose that was connected to a piezoelectric force gauge. Experiments with teeball bats weighing 295-485 g demonstrated that 12-20 kN forces were necessary to cause a comparable bat fracture. In addition to physical testing, a computer-aided simulation was conducted, utilizing a finite-element (FE) method. In the FE approach, after selecting for wood properties, a virtual bat was swung against a hemisphere comprising two layers that represented bone and soft tissue. Employing this model, a 17.6 kN force was calculated, with the highest fracture probability points resembling the fracture patterns of the physically tested bats.},
keywords = {*Computer Simulation, *Forensic Pathology/mt [Methods], *HEAD injuries, *Models, *Skull Fractures/pa [Pathology], *Skull/pa [Pathology], *Sports Equipment, *Weapons, Anatomic, Biological, Biomechanical Phenomena, Closed/pa [Pathology], Equipment Design, finite element analysis, Humans, Skull/in [Injuries], violence, Wood, Young Adult},
pubstate = {published},
tppubtype = {article}
}
Fahlstedt, M; Halldin, P; Kleiven, S
The protective effect of a helmet in three bicycle accidents--A finite element study Journal Article
In: Accident Analysis & Prevention, vol. 91, pp. 135–143, 2016.
@article{Fahlstedt2016,
title = {The protective effect of a helmet in three bicycle accidents--A finite element study},
author = {Fahlstedt, M and Halldin, P and Kleiven, S},
year = {2016},
date = {2016-01-01},
journal = {Accident Analysis \& Prevention},
volume = {91},
pages = {135--143},
abstract = {There is some controversy regarding the effectiveness of helmets in preventing head injuries among cyclists. Epidemiological, experimental and computer simulation studies have suggested that helmets do indeed have a protective effect, whereas other studies based on epidemiological data have argued that there is no evidence that the helmet protects the brain. The objective of this study was to evaluate the protective effect of a helmet in single bicycle accident reconstructions using detailed finite element simulations. Strain in the brain tissue, which is associated with brain injuries, was reduced by up to 43% for the accident cases studied when a helmet was included. This resulted in a reduction of the risk of concussion of up to 54%. The stress to the skull bone went from fracture level of 80 MPa down to 13-16 MPa when a helmet was included and the skull fracture risk was reduced by up to 98% based on linear acceleration. Even with a 10% increased riding velocity for the helmeted impacts, to take into account possible increased risk taking, the risk of concussion was still reduced by up to 46% when compared with the unhelmeted impacts with original velocity. The results of this study show that the brain injury risk and risk of skull fracture could have been reduced in these three cases if a helmet had been worn.Copyright © 2016 Elsevier Ltd. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Johnson, K L; Chowdhury, S; Lawrimore, W B; Mao, Y; Mehmani, A; Prabhu, R; Rush, G A; Horstemeyer, M F
Constrained topological optimization of a football helmet facemask based on brain response Journal Article
In: Materials and Design, vol. 111, pp. 108–118, 2016.
@article{Johnson2016a,
title = {Constrained topological optimization of a football helmet facemask based on brain response},
author = {Johnson, K L and Chowdhury, S and Lawrimore, W B and Mao, Y and Mehmani, A and Prabhu, R and Rush, G A and Horstemeyer, M F},
doi = {10.1016/j.matdes.2016.08.064},
year = {2016},
date = {2016-01-01},
journal = {Materials and Design},
volume = {111},
pages = {108--118},
abstract = {Surrogate model-based multi-objective design optimization was performed to reduce concussion risk during frontal football helmet impacts. In particular, a topological decomposition of the football helmet facemask was performed to formulate the design problem, and brain injury metrics were exploited as objective functions. A validated finite element model of a helmeted human head was used to recreate facemask impacts. Due to the prohibitive computational expense of the full scale simulations, a surrogate modeling approach was employed. An optimal surrogate model selection framework, called Concurrent Surrogate Model Selection, or COSMOS, was utilized to identify the surrogate models best suited to approximate each objective function. The resulting surrogate models were implemented in the Non-dominated Sorting Genetic Algorithm II (NSGA-II) optimization algorithm. Constraints were implemented to control the solid material fraction in the facemask design space, and binary variables were used to control the placement of the facemask bars. The optimized facemask designs reduced the maximum tensile pressure in the brain by 7.5% and the maximum shear strain by a remarkable 39.5%. This research represents a first-of-its-kind approach to multi-objective design optimization on a football helmet, and demonstrates the possibilities that are achievable in improving human safety by using such a simulation-based design optimization. © 2016 Elsevier Ltd},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Oeur, R A; Karton, C; Post, A; Rousseau, P; Hoshizaki, T B; Marshall, S; Brien, S E; Smith, A; Cusimano, M D; Gilchrist, M D
In: Journal of Neurosurgery, vol. 123, no. 2, pp. 415–422, 2015.
@article{Oeur2015,
title = {A comparison of head dynamic response and brain tissue stress and strain using accident reconstructions for concussion, concussion with persistent postconcussive symptoms, and subdural hematoma},
author = {Oeur, R A and Karton, C and Post, A and Rousseau, P and Hoshizaki, T B and Marshall, S and Brien, S E and Smith, A and Cusimano, M D and Gilchrist, M D},
doi = {10.3171/2014.10.JNS14440},
year = {2015},
date = {2015-01-01},
journal = {Journal of Neurosurgery},
volume = {123},
number = {2},
pages = {415--422},
abstract = {Object Concussions typically resolve within several days, but in a few cases the symptoms last for a month or longer and are termed persistent postconcussive symptoms (PPCS). These persisting symptoms may also be associated with more serious brain trauma similar to subdural hematoma (SDH). The objective of this study was to investigate the head dynamic and brain tissue responses of injury reconstructions resulting in concussion, PPCS, and SDH. Methods Reconstruction cases were obtained from sports medicine clinics and hospitals. All subjects received a direct blow to the head resulting in symptoms. Those symptoms that resolved in 9 days or fewer were defined as concussions (n = 3). Those with symptoms lasting longer than 18 months were defined as PPCS (n = 3), and 3 patients presented with SDHs (n = 3). A Hybrid III headform was used in reconstruction to obtain linear and rotational accelerations of the head. These dynamic response data were then input into the University College Dublin Brain Trauma Model to calculate maximum principal strain and von Mises stress. A Kruskal-Wallis test followed by Tukey post hoc tests were used to compare head dynamic and brain tissue responses between injury groups. Statistical significance was set at p \< 0.05. Results A significant difference was identified for peak resultant linear and rotational acceleration between injury groups. Post hoc analyses revealed the SDH group had higher linear and rotational acceleration responses (316 g and 23,181 rad/sec2, respectively) than the concussion group (149 g and 8111 rad/sec2, respectively; p \< 0.05). No significant differences were found between groups for either brain tissue measures of maximum principal strain or von Mises stress. Conclusions The reconstruction of accidents resulting in a concussion with transient symptoms (low severity) and SDHs revealed a positive relationship between an increase in head dynamic response and the risk for more serious brain injury. This type of relationship was not found for brain tissue stress and strain results derived by finite element analysis. Future research should be undertaken using a larger sample size to confirm these initial findings. Understanding the relationship between the head dynamic and brain tissue response and the nature of the injury provides important information for developing strategies for injury prevention. © AANS, 2015.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Patton, D A; McIntosh, A S; Kleiven, S
In: Journal of Applied Biomechanics, vol. 31, no. 4, pp. 264–268, 2015.
@article{Patton2015,
title = {The biomechanical determinants of concussion: Finite element simulations to investigate tissue-level predictors of injury during sporting impacts to the unprotected head},
author = {Patton, D A and McIntosh, A S and Kleiven, S},
doi = {10.1123/jab.2014-0223},
year = {2015},
date = {2015-01-01},
journal = {Journal of Applied Biomechanics},
volume = {31},
number = {4},
pages = {264--268},
abstract = {Biomechanical studies of concussions have progressed from qualitative observations of head impacts to physical and numerical reconstructions, direct impact measurements, and finite element analyses. Supplementary to a previous study, which investigated maximum principal strain, the current study used a detailed finite element head model to simulate unhelmeted concussion and no-injury head impacts and evaluate the effectiveness of various tissue-level brain injury predictors: strain rate, product of strain and strain rate, cumulative strain damage measure, von Mises stress, and intracranial pressure. Von Mises stress was found to be the most effective predictor of concussion. It was also found that the thalamus and corpus callosum were brain regions with strong associations with concussion. Tentative tolerance limits for tissue-level predictors were proposed in an attempt to broaden the understanding of unhelmeted concussions. For the thalamus, tolerance limits were proposed for a 50% likelihood of concussion: 2.24 kPa, 24.0 s-1, and 2.49 s-1 for von Mises stress, strain rate, and the product of strain and strain rate, respectively. For the corpus callosum, tolerance limits were proposed for a 50% likelihood of concussion: 3.51 kPa, 25.1 s-1, and 2.76 s-1 for von Mises stress, strain rate, and the product of strain and strain rate, respectively. © 2015 Human Kinetics, Inc.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Bartsch, A; Samorezov, S; Benzel, E; Miele, V; Brett, D
Validation of an "Intelligent Mouthguard" Single Event Head Impact Dosimeter Journal Article
In: Stapp Car Crash Journal, vol. 58, pp. 1–27, 2014.
@article{Bartsch2014,
title = {Validation of an "Intelligent Mouthguard" Single Event Head Impact Dosimeter},
author = {Bartsch, A and Samorezov, S and Benzel, E and Miele, V and Brett, D},
year = {2014},
date = {2014-01-01},
journal = {Stapp Car Crash Journal},
volume = {58},
pages = {1--27},
abstract = {Dating to Colonel John Paul Stapp MD in 1975, scientists have desired to measure live human head impacts with accuracy and precision. But no instrument exists to accurately and precisely quantify single head impact events. Our goal is to develop a practical single event head impact dosimeter known as "Intelligent Mouthguard" and quantify its performance on the benchtop, in vitro and in vivo. In the Intelligent Mouthguard hardware, limited gyroscope bandwidth requires an algorithm-based correction as a function of impact duration. After we apply gyroscope correction algorithm, Intelligent Mouthguard results at time of CG linear acceleration peak correlate to the Reference Hybrid III within our tested range of pulse durations and impact acceleration profiles in American football and Boxing in vitro tests: American football},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Kettner, M; Ramsthaler, F; Potente, S; Bockenheimer, A; Schmidt, P H; Schrodt, M
Blunt force impact to the head using a teeball bat: systematic comparison of physical and finite element modeling Journal Article
In: Forensic Science, Medicine & Pathology, vol. 10, no. 4, pp. 513–517, 2014.
@article{Kettner2014,
title = {Blunt force impact to the head using a teeball bat: systematic comparison of physical and finite element modeling},
author = {Kettner, M and Ramsthaler, F and Potente, S and Bockenheimer, A and Schmidt, P H and Schrodt, M},
year = {2014},
date = {2014-01-01},
journal = {Forensic Science, Medicine \& Pathology},
volume = {10},
number = {4},
pages = {513--517},
abstract = {Blunt head trauma secondary to violent actions with various weapons is frequently a cause of injury in forensic casework; differing striking tools have varying degrees of injury capacity. The systematic approach used to examine a 19-year-old student who was beaten with a wooden teeball bat will be described. The assailant stopped beating the student when the teeball bat broke into two pieces. The surviving victim sustained bruises and a forehead laceration. The State's Attorney assigned a forensic expert to examine whether the forces exerted on the victim's head (leading to the fracture of the bat) were potentially life threatening (e.g. causing cranial bone fractures). Physical modeling was conducted using a pigskin-covered polyethylene end cap cushioned by cellulose that was connected to a piezoelectric force gauge. Experiments with teeball bats weighing 295-485 g demonstrated that 12-20 kN forces were necessary to cause a comparable bat fracture. In addition to physical testing, a computer-aided simulation was conducted, utilizing a finite-element (FE) method. In the FE approach, after selecting for wood properties, a virtual bat was swung against a hemisphere comprising two layers that represented bone and soft tissue. Employing this model, a 17.6 kN force was calculated, with the highest fracture probability points resembling the fracture patterns of the physically tested bats.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Fahlstedt, M; Halldin, P; Kleiven, S
The protective effect of a helmet in three bicycle accidents--A finite element study Journal Article
In: Accident Analysis & Prevention, vol. 91, pp. 135–143, 2016.
Abstract | BibTeX | Tags: *Accidents, *Bicycling/in [Injuries], *Brain Concussion/pc [Prevention & Control], *Head Protective Devices, *Skull Fractures/pc [Prevention & Control], Computer simulation, Craniocerebral Trauma/pc [Prevention & Control], finite element analysis, Humans, Traffic
@article{Fahlstedt2016,
title = {The protective effect of a helmet in three bicycle accidents--A finite element study},
author = {Fahlstedt, M and Halldin, P and Kleiven, S},
year = {2016},
date = {2016-01-01},
journal = {Accident Analysis \& Prevention},
volume = {91},
pages = {135--143},
abstract = {There is some controversy regarding the effectiveness of helmets in preventing head injuries among cyclists. Epidemiological, experimental and computer simulation studies have suggested that helmets do indeed have a protective effect, whereas other studies based on epidemiological data have argued that there is no evidence that the helmet protects the brain. The objective of this study was to evaluate the protective effect of a helmet in single bicycle accident reconstructions using detailed finite element simulations. Strain in the brain tissue, which is associated with brain injuries, was reduced by up to 43% for the accident cases studied when a helmet was included. This resulted in a reduction of the risk of concussion of up to 54%. The stress to the skull bone went from fracture level of 80 MPa down to 13-16 MPa when a helmet was included and the skull fracture risk was reduced by up to 98% based on linear acceleration. Even with a 10% increased riding velocity for the helmeted impacts, to take into account possible increased risk taking, the risk of concussion was still reduced by up to 46% when compared with the unhelmeted impacts with original velocity. The results of this study show that the brain injury risk and risk of skull fracture could have been reduced in these three cases if a helmet had been worn.Copyright © 2016 Elsevier Ltd. All rights reserved.},
keywords = {*Accidents, *Bicycling/in [Injuries], *Brain Concussion/pc [Prevention \& Control], *Head Protective Devices, *Skull Fractures/pc [Prevention \& Control], Computer simulation, Craniocerebral Trauma/pc [Prevention \& Control], finite element analysis, Humans, Traffic},
pubstate = {published},
tppubtype = {article}
}
Johnson, K L; Chowdhury, S; Lawrimore, W B; Mao, Y; Mehmani, A; Prabhu, R; Rush, G A; Horstemeyer, M F
Constrained topological optimization of a football helmet facemask based on brain response Journal Article
In: Materials and Design, vol. 111, pp. 108–118, 2016.
Abstract | Links | BibTeX | Tags: Accident prevention, ALGORITHMS, brain, Concussion, Constrained optimization, Design, Design optimization, finite element analysis, Finite element method, football helmet, Fuel additives, Genetic algorithms, Multiobjective optimization, Optimization, Safety devices, Shear strain, Sports, Surrogate model, Surrogate modeling, Topology, Traumatic Brain Injuries, traumatic brain injury
@article{Johnson2016a,
title = {Constrained topological optimization of a football helmet facemask based on brain response},
author = {Johnson, K L and Chowdhury, S and Lawrimore, W B and Mao, Y and Mehmani, A and Prabhu, R and Rush, G A and Horstemeyer, M F},
doi = {10.1016/j.matdes.2016.08.064},
year = {2016},
date = {2016-01-01},
journal = {Materials and Design},
volume = {111},
pages = {108--118},
abstract = {Surrogate model-based multi-objective design optimization was performed to reduce concussion risk during frontal football helmet impacts. In particular, a topological decomposition of the football helmet facemask was performed to formulate the design problem, and brain injury metrics were exploited as objective functions. A validated finite element model of a helmeted human head was used to recreate facemask impacts. Due to the prohibitive computational expense of the full scale simulations, a surrogate modeling approach was employed. An optimal surrogate model selection framework, called Concurrent Surrogate Model Selection, or COSMOS, was utilized to identify the surrogate models best suited to approximate each objective function. The resulting surrogate models were implemented in the Non-dominated Sorting Genetic Algorithm II (NSGA-II) optimization algorithm. Constraints were implemented to control the solid material fraction in the facemask design space, and binary variables were used to control the placement of the facemask bars. The optimized facemask designs reduced the maximum tensile pressure in the brain by 7.5% and the maximum shear strain by a remarkable 39.5%. This research represents a first-of-its-kind approach to multi-objective design optimization on a football helmet, and demonstrates the possibilities that are achievable in improving human safety by using such a simulation-based design optimization. © 2016 Elsevier Ltd},
keywords = {Accident prevention, ALGORITHMS, brain, Concussion, Constrained optimization, Design, Design optimization, finite element analysis, Finite element method, football helmet, Fuel additives, Genetic algorithms, Multiobjective optimization, Optimization, Safety devices, Shear strain, Sports, Surrogate model, Surrogate modeling, Topology, Traumatic Brain Injuries, traumatic brain injury},
pubstate = {published},
tppubtype = {article}
}
Oeur, R A; Karton, C; Post, A; Rousseau, P; Hoshizaki, T B; Marshall, S; Brien, S E; Smith, A; Cusimano, M D; Gilchrist, M D
In: Journal of Neurosurgery, vol. 123, no. 2, pp. 415–422, 2015.
Abstract | Links | BibTeX | Tags: accident, Accident reconstruction, accidental injury, Accidents, Adolescent, adult, Article, Biomechanical Phenomena, Biomechanics, brain, brain concussion, brain stem, brain tissue, Cerebellum, clinical article, comparative study, Concussion, controlled study, Female, finite element analysis, Finite element modelling, gray matter, Hematoma, human, Humans, Hybrid iii headform, injury severity, laboratory test, Male, Mechanical, mechanical stress, middle aged, pathology, Pathophysiology, Persistent postconcussive symptoms, PHYSIOLOGY, Post Hoc Analysis, Post-Concussion Syndrome, postconcussion syndrome, priority journal, shear stress, simulation, SPORTS medicine, STATISTICAL significance, Stress, stress strain relationship, Subdural, subdural hematoma, traumatic brain injury, white matter, Young Adult
@article{Oeur2015,
title = {A comparison of head dynamic response and brain tissue stress and strain using accident reconstructions for concussion, concussion with persistent postconcussive symptoms, and subdural hematoma},
author = {Oeur, R A and Karton, C and Post, A and Rousseau, P and Hoshizaki, T B and Marshall, S and Brien, S E and Smith, A and Cusimano, M D and Gilchrist, M D},
doi = {10.3171/2014.10.JNS14440},
year = {2015},
date = {2015-01-01},
journal = {Journal of Neurosurgery},
volume = {123},
number = {2},
pages = {415--422},
abstract = {Object Concussions typically resolve within several days, but in a few cases the symptoms last for a month or longer and are termed persistent postconcussive symptoms (PPCS). These persisting symptoms may also be associated with more serious brain trauma similar to subdural hematoma (SDH). The objective of this study was to investigate the head dynamic and brain tissue responses of injury reconstructions resulting in concussion, PPCS, and SDH. Methods Reconstruction cases were obtained from sports medicine clinics and hospitals. All subjects received a direct blow to the head resulting in symptoms. Those symptoms that resolved in 9 days or fewer were defined as concussions (n = 3). Those with symptoms lasting longer than 18 months were defined as PPCS (n = 3), and 3 patients presented with SDHs (n = 3). A Hybrid III headform was used in reconstruction to obtain linear and rotational accelerations of the head. These dynamic response data were then input into the University College Dublin Brain Trauma Model to calculate maximum principal strain and von Mises stress. A Kruskal-Wallis test followed by Tukey post hoc tests were used to compare head dynamic and brain tissue responses between injury groups. Statistical significance was set at p \< 0.05. Results A significant difference was identified for peak resultant linear and rotational acceleration between injury groups. Post hoc analyses revealed the SDH group had higher linear and rotational acceleration responses (316 g and 23,181 rad/sec2, respectively) than the concussion group (149 g and 8111 rad/sec2, respectively; p \< 0.05). No significant differences were found between groups for either brain tissue measures of maximum principal strain or von Mises stress. Conclusions The reconstruction of accidents resulting in a concussion with transient symptoms (low severity) and SDHs revealed a positive relationship between an increase in head dynamic response and the risk for more serious brain injury. This type of relationship was not found for brain tissue stress and strain results derived by finite element analysis. Future research should be undertaken using a larger sample size to confirm these initial findings. Understanding the relationship between the head dynamic and brain tissue response and the nature of the injury provides important information for developing strategies for injury prevention. © AANS, 2015.},
keywords = {accident, Accident reconstruction, accidental injury, Accidents, Adolescent, adult, Article, Biomechanical Phenomena, Biomechanics, brain, brain concussion, brain stem, brain tissue, Cerebellum, clinical article, comparative study, Concussion, controlled study, Female, finite element analysis, Finite element modelling, gray matter, Hematoma, human, Humans, Hybrid iii headform, injury severity, laboratory test, Male, Mechanical, mechanical stress, middle aged, pathology, Pathophysiology, Persistent postconcussive symptoms, PHYSIOLOGY, Post Hoc Analysis, Post-Concussion Syndrome, postconcussion syndrome, priority journal, shear stress, simulation, SPORTS medicine, STATISTICAL significance, Stress, stress strain relationship, Subdural, subdural hematoma, traumatic brain injury, white matter, Young Adult},
pubstate = {published},
tppubtype = {article}
}
Patton, D A; McIntosh, A S; Kleiven, S
In: Journal of Applied Biomechanics, vol. 31, no. 4, pp. 264–268, 2015.
Abstract | Links | BibTeX | Tags: Article, Biomechanics, brain, Brain Injury, brain region, clinical article, Concussion, corpus callosum, Damage detection, evaluation study, finite element analysis, Finite element head models, Finite element method, Finite element simulations, football, gray matter, Head Injuries, head injury, human, Intra-cranial pressure, intracranial pressure, investigative procedures, Maximum principal strain, mesencephalon, Modeling, Models, Numerical reconstruction, Qualitative observations, Sport, sport injury, Sports, Strain and strain rates, Strain rate, Stress, thalamus, Tissue, tissue level
@article{Patton2015,
title = {The biomechanical determinants of concussion: Finite element simulations to investigate tissue-level predictors of injury during sporting impacts to the unprotected head},
author = {Patton, D A and McIntosh, A S and Kleiven, S},
doi = {10.1123/jab.2014-0223},
year = {2015},
date = {2015-01-01},
journal = {Journal of Applied Biomechanics},
volume = {31},
number = {4},
pages = {264--268},
abstract = {Biomechanical studies of concussions have progressed from qualitative observations of head impacts to physical and numerical reconstructions, direct impact measurements, and finite element analyses. Supplementary to a previous study, which investigated maximum principal strain, the current study used a detailed finite element head model to simulate unhelmeted concussion and no-injury head impacts and evaluate the effectiveness of various tissue-level brain injury predictors: strain rate, product of strain and strain rate, cumulative strain damage measure, von Mises stress, and intracranial pressure. Von Mises stress was found to be the most effective predictor of concussion. It was also found that the thalamus and corpus callosum were brain regions with strong associations with concussion. Tentative tolerance limits for tissue-level predictors were proposed in an attempt to broaden the understanding of unhelmeted concussions. For the thalamus, tolerance limits were proposed for a 50% likelihood of concussion: 2.24 kPa, 24.0 s-1, and 2.49 s-1 for von Mises stress, strain rate, and the product of strain and strain rate, respectively. For the corpus callosum, tolerance limits were proposed for a 50% likelihood of concussion: 3.51 kPa, 25.1 s-1, and 2.76 s-1 for von Mises stress, strain rate, and the product of strain and strain rate, respectively. © 2015 Human Kinetics, Inc.},
keywords = {Article, Biomechanics, brain, Brain Injury, brain region, clinical article, Concussion, corpus callosum, Damage detection, evaluation study, finite element analysis, Finite element head models, Finite element method, Finite element simulations, football, gray matter, Head Injuries, head injury, human, Intra-cranial pressure, intracranial pressure, investigative procedures, Maximum principal strain, mesencephalon, Modeling, Models, Numerical reconstruction, Qualitative observations, Sport, sport injury, Sports, Strain and strain rates, Strain rate, Stress, thalamus, Tissue, tissue level},
pubstate = {published},
tppubtype = {article}
}
Bartsch, A; Samorezov, S; Benzel, E; Miele, V; Brett, D
Validation of an "Intelligent Mouthguard" Single Event Head Impact Dosimeter Journal Article
In: Stapp Car Crash Journal, vol. 58, pp. 1–27, 2014.
Abstract | BibTeX | Tags: *Acceleration, *Boxing, *Brain Injuries, *Football, *Mouth Protectors, *Telemetry, ALGORITHMS, Biomechanical Phenomena/ph [Physiology], Boxing/in [Injuries], Boxing/ph [Physiology], Brain Injuries/di [Diagnosis], Brain Injuries/et [Etiology], Brain Injuries/pc [Prevention & Control], Brain Injuries/pp [Physiopathology], finite element analysis, Football/in [Injuries], Football/ph [Physiology], Head Protective Devices, Humans, Reproducibility of Results, Telemetry/is [Instrumentation], Telemetry/mt [Methods]
@article{Bartsch2014,
title = {Validation of an "Intelligent Mouthguard" Single Event Head Impact Dosimeter},
author = {Bartsch, A and Samorezov, S and Benzel, E and Miele, V and Brett, D},
year = {2014},
date = {2014-01-01},
journal = {Stapp Car Crash Journal},
volume = {58},
pages = {1--27},
abstract = {Dating to Colonel John Paul Stapp MD in 1975, scientists have desired to measure live human head impacts with accuracy and precision. But no instrument exists to accurately and precisely quantify single head impact events. Our goal is to develop a practical single event head impact dosimeter known as "Intelligent Mouthguard" and quantify its performance on the benchtop, in vitro and in vivo. In the Intelligent Mouthguard hardware, limited gyroscope bandwidth requires an algorithm-based correction as a function of impact duration. After we apply gyroscope correction algorithm, Intelligent Mouthguard results at time of CG linear acceleration peak correlate to the Reference Hybrid III within our tested range of pulse durations and impact acceleration profiles in American football and Boxing in vitro tests: American football},
keywords = {*Acceleration, *Boxing, *Brain Injuries, *Football, *Mouth Protectors, *Telemetry, ALGORITHMS, Biomechanical Phenomena/ph [Physiology], Boxing/in [Injuries], Boxing/ph [Physiology], Brain Injuries/di [Diagnosis], Brain Injuries/et [Etiology], Brain Injuries/pc [Prevention \& Control], Brain Injuries/pp [Physiopathology], finite element analysis, Football/in [Injuries], Football/ph [Physiology], Head Protective Devices, Humans, Reproducibility of Results, Telemetry/is [Instrumentation], Telemetry/mt [Methods]},
pubstate = {published},
tppubtype = {article}
}
Kettner, M; Ramsthaler, F; Potente, S; Bockenheimer, A; Schmidt, P H; Schrodt, M
Blunt force impact to the head using a teeball bat: systematic comparison of physical and finite element modeling Journal Article
In: Forensic Science, Medicine & Pathology, vol. 10, no. 4, pp. 513–517, 2014.
Abstract | BibTeX | Tags: *Computer Simulation, *Forensic Pathology/mt [Methods], *HEAD injuries, *Models, *Skull Fractures/pa [Pathology], *Skull/pa [Pathology], *Sports Equipment, *Weapons, Anatomic, Biological, Biomechanical Phenomena, Closed/pa [Pathology], Equipment Design, finite element analysis, Humans, Skull/in [Injuries], violence, Wood, Young Adult
@article{Kettner2014,
title = {Blunt force impact to the head using a teeball bat: systematic comparison of physical and finite element modeling},
author = {Kettner, M and Ramsthaler, F and Potente, S and Bockenheimer, A and Schmidt, P H and Schrodt, M},
year = {2014},
date = {2014-01-01},
journal = {Forensic Science, Medicine \& Pathology},
volume = {10},
number = {4},
pages = {513--517},
abstract = {Blunt head trauma secondary to violent actions with various weapons is frequently a cause of injury in forensic casework; differing striking tools have varying degrees of injury capacity. The systematic approach used to examine a 19-year-old student who was beaten with a wooden teeball bat will be described. The assailant stopped beating the student when the teeball bat broke into two pieces. The surviving victim sustained bruises and a forehead laceration. The State's Attorney assigned a forensic expert to examine whether the forces exerted on the victim's head (leading to the fracture of the bat) were potentially life threatening (e.g. causing cranial bone fractures). Physical modeling was conducted using a pigskin-covered polyethylene end cap cushioned by cellulose that was connected to a piezoelectric force gauge. Experiments with teeball bats weighing 295-485 g demonstrated that 12-20 kN forces were necessary to cause a comparable bat fracture. In addition to physical testing, a computer-aided simulation was conducted, utilizing a finite-element (FE) method. In the FE approach, after selecting for wood properties, a virtual bat was swung against a hemisphere comprising two layers that represented bone and soft tissue. Employing this model, a 17.6 kN force was calculated, with the highest fracture probability points resembling the fracture patterns of the physically tested bats.},
keywords = {*Computer Simulation, *Forensic Pathology/mt [Methods], *HEAD injuries, *Models, *Skull Fractures/pa [Pathology], *Skull/pa [Pathology], *Sports Equipment, *Weapons, Anatomic, Biological, Biomechanical Phenomena, Closed/pa [Pathology], Equipment Design, finite element analysis, Humans, Skull/in [Injuries], violence, Wood, Young Adult},
pubstate = {published},
tppubtype = {article}
}